Fornia



E. E. wlckERsHAM. CONSTRUCTION FOR TRACTION ENGINES.

l APPIICATION. FILED OCT.A 24, 1918. 1,429,472.

wn. n@ avm 07m/VJ www Ss F ZM m fl] m i E. E. WICKERSHAM. CONSTRUCTION FOR TRACTION ENGINESl APPucATxoN FILED ocT.24.191s.

'Pa-tenasept. 19,1922.

2 SHEETS-SHEET 2\ Patented Sept. 19, 1922.

UNIIED STATES PATENT ONF-Fics,

ELMER E. WICKERSHAM, Aor sTocIrToN, CALIFORNIA, AssrGNon To Tnn noLr MANU- FACTURING COMPANY, or sroCK'roN, CALIFORNIA, A ConronA'rroN on CALL FORNIA.

CONSTRUCTION non 'rnAcrIoN ENGINES.

Application led October 24, 1918. Serial No, 259,583.

To all whom it may concern:

Be it known that I, ELMER'E. VVICKER- SHAM, a citizen of theUnited States, residing at Stockton, in the county of S'an Joaquin and State of California, have yinvented new and useful Improvement in Construction for Traction Engines, vof which the following is a speci'cation.

This invention relates to a tractor construction and particularly pertains to a tractor of the self-laying chain track type.

Due to the fact that tractors are necessarily of heavy construction andare rigid in their structure, it has been a matter of considerable consideration to provide a tractor of the self-laying chain track typo with a suitable frame suspension by which the body of the tractor may be supported in a flexible manner land at the same time allow the lower run of chain to easily'conform to the contour of the roadway.

It is the principal object `of lthe present invention to provide a running gear mechanism for chain typetractors `adaptable to flexibly support the mainframe and to yieldably rest upon'they chain tread.

The present invention contemplates the use of roller trucks pivotally connected to the main yframe of a tractor at their rear ends and at a point in the rear of the axes of the chain track driving sprockets and supporting the forward end of the'tractor by a yieldable equalizing mechanism, the opposite ends of said trucks carrylng'the driving sprockets andidler wheels for chain tracks while the intermediate portions of the trucks carry a series' of'jsepara'te yieldable load supporting rollers adapted to bear upon the lower run of track and to primai-ily support the vehicle. This'invention is illustrated by way of example in the accompanying drawings in whichl Fig. 1 is a view in side' elevation `villustrating the complete and asscmbledytracks and particularly disclosing the construction of the chain track truck, the frame'suspension and thetractor driving mechanism, parts ofthe chain tread being broken away for clearness.

F ig. 2 is a view in transverse section as seen on line 2--2 of Fig. 1, illustrating the truck construction and the manner in which the separate track rollers are supported.

Fig. 3 is a view in plan illustrating the tractor main frame as supported upon selflaying track units at the opposite sides thereof, said units being shown without their chain tracks and further disclosing a fragmentary portion of the power transmission mechanism.

Referring more particularly to the drawings, 1() indicates aftractor main frame here shown as formed ofl rigidly united side rails and end bars. Positioned uponthis frame is a powerplant 11 adapted to drive a transmission'mechanism 12. The opposite ends of this mechanism are provided with driving shafts v13 which extend outwardly through bearings upon the main frame and are there vfitted with driving sprockets 14. Sprocket vchains 15 lead around these'sprockets and tivo larger driving sprockets 16 upon va jack shaft `17. This last named shaft is vnon-rotatably held within bearings secured directly-beneath.. and to the rear end of the mainframe. Mounted upon vthe jack shaft and upon the outside of the sprocket 16 are sprockets 18 which cooperate with enlarged driving sprockets 19 to receive final drive chains 20. The sprockets 16 and 18 are mounted upon ianged journals towhichjthey are bolted. These journals areheld in position upon the shaft 17 by means of collars at their outer ends and are free'to rotate around the shaft. The large sprockets are fixed around the axles 21 of ythe chain track sprockets 22. It, will be understood that these sprockets andy idler sprockets 23 receive link chain tracks 24 upon which the vehicle is propelled.

Pivotally secured to the jack shaft 17 are track trucks. These trucks consist of outer rails 25, extending parallel to the main frame and having'bearings at their rear end rwhich are rotatably mounted on 'the outer fends' of the jack shaft and inner rails 26 which stand parallel with the rails 25 for a major portionof-their length and thereafter 'are bent inwardly to engage the jack shaft ata 'point near the center of the main frame and therebeneath. The forward ends of the rails 25 and 26 are fitted with bearings 27 for receiving the axle of the idlers 28. The opposite ends are fitted with bearings 28 for receiving the aXle of the chain track driving sprockets 22.

Positioned at intervals along the underside of each of the rails and between the idler wheels 23 and sprockets 22 are load supporting rollers 29. These rollers are arranged in pairs as shown, in Fig. 2 and are adapted to bear upon the upper tace oit the lower run of track chain. The rollers are mounted on the ends oi cantilever arms 30. These arms are inclined at an angle to the vertical and are pivoted upon pins 3l. carried by the bearings 32. Each et these levers is formed with an upwardly edending,l linger which is enlafroed to provide pad Sil at its upper end. 'l his pad is perforated to receive a cushion rod 35, one oit which rods extends midway between the rails and 26 oil? each trucl:` and is oi: a length to 'terminate between the sprockets and idlers Secured across the rails are brackets 36 which also carry pads through which the rods extend. li'iterposed between the pads ot' 'the lingers and complementary pads of' the brackets are helical compression springs 3T. Thus, power is exertedto swing` the rollers 29 upwardly, this motion will be resisted by the compres sion oi.E the springs 87 as they act between .the lingers and the cross trame members.

The rollers 29 which are nearest the idler wheels 28 are provided with crank arms which are formed to swing in unison with the cantileverarms 30 and to which one end oi the rods 35 pivotally connect. The opposite ends of these rods extend through crosslrame members 39 disposed between the sprech-et wheels 22 and the nearest roller and are there iitted with springs l0 which act between the cross-member and a washer on the end oit the rod. Thus, as the arm 88 is thrown forwardly the spring el() will be compressed. i i

The main frame is Vtree to float in relation to the forward ends oil the truck irames and is suspended by an equalizing mecha nism to reduce. the relative movement of the main frame in relation 'to the separate truck units to a minimum. This mechanism consists oi' cross-blocks l1 secured to each of the roller 'frames and providing support for a pressure arm 42. These arms stand in the same plane at opposite sides of the main iframe, and are fixed to rotate around shafts et?) supported at the opposite sides ot the main trame. These sha'lts also carry levers ll which pivotally engage sleeves l5 at their upper ends. The sleeves are lined upon side rods i6 which extend along the opposite Sides ot the main 'frame and parallel thereto. The ends of these rods are provided with?` washers l? and between these washers and the sleeves compression springs i8 are positioned. The rods extend torwardly and engage an equalizer bar i9 at their toiwvard terminating ends. This bar is centrallyT pivotcd upon a pin 50 to a bracket 51 which is mounted at the center of the front `cross rail oli' the main iframe. Tn the present instance7 the bar lil-9 has been secured across the :trent oit the. main frame. 1t will be evident, however, that the bar could be secured across the main frame at a point direc'tlyin `liront oi the arms ed, it desired, or it might be disposed at any point in the rear of these arms without impairing its operation. Thus, as the rods /lG are pivoted to the opposite ends el: the bar, it will be seen that the two rods will be interconnected and that movement of one in a single direction will produce contrary movement of the other.

operation the vehicle is propelled by e chains 2O to rotate the axles 21 c i i chain tread sproclliets In order to profile proper clearance, idler wheels 15 are l A`posed beneath the lower runoi:l each or the chains i5. .As ,the vehicle passes along lthe highway, inequality in the Lcontour of the roadbed will be locally aecom-v modated by the flexing' ot the arms 30 and the resultant upward movement of the indi vidual rollers 29, thus reducing the vibra tion oi' the main tramo normally altected by small irregularities in the lroadbed. il nen the reached upon opposite sides o't' the vehicle; is out oit level, one of the truck mes will swingl` upwardly as pivotally gorted from the jack shaft 1'?. Thisac- 100 tio.; will swing the corresponding pressure I arms 472 upwrV diy and will cause it to force against tno complementary spring 48. Upon compressing' this spring', the rod 46 willbe drawn and this in turn will move the oppo- .site rod in an opposite directiomthus acting to force the other pressure arm downwardly. .if-1s the two roller trames and the chain tracks are rigidi;T supported upon the ground, the ellect will be to raise the main frame bali the distance ot the diiference in level 'between 1die roller trames, thereby equalizino' the movement oi the roller 'frames and reducing the vibration of the main frame to v a minimum. Y 115 Reference being had particularly to Fig. i l, itwill lhe noted that the roller truck frames are supported to swing from a point in =the rear ot' the axis oit the driving sprockets 22 and that this swinging. action will bel `resisted by the equalizer mechanism interposed between theflforward i'ree ends oit the truck trames and the main frame. By this arran gement,the drivingchain 2O leading from theI sprocket 18 to the drivingl sprocket 19 will always he .in the samer condition of tension irrespective oi the swinginginovement of the separate `truck rollers in relation to the main frame.

It will thus be seenJ thatpfthe frame suspension here shown, while simple in its construction, allows the chain track to conform to the contour of the ground over which it passes, at the same time permitting an equalization of the movements ot' the two truck units without interruption of power in the chains.

IIaving thus described my invention, what I claim and desire to secure by Letters Patent is- 1. In a tractor construction, a main frame, track units at the opposite sides of said main frame and including driving sprockets, idler wheels, truck :trames and track chains embracing the sprockets and wheels, means for pivotally connecting said truck units to the main Jframe at points in the rear of the driving sprockets, and yield ing connections between the truck frames and the main frame permitting yrocking movement of the truck frames about their rear pivotal connection with the main frame under operative conditions.

2. In a tractor construction, a main frame, track units at the opposite sides oisaid main frame and including driving sprockets, idler wheels, truck frames and track chains embracing the sprockets and wheels, means for pivotally connecting said truck units to the main frame at points in the rear of the driving sprockets, means for driving the sprockets of the track units from the axis of said point of connection, and yielding connections between the truck frames and the main frame permitting rocking movement of the truck frames about their rear pivotal connection with the main iframe under operative conditions.

3. In a tractor construction, a main frame, roller truck frames at the oppo` site sides thereof, idler wheels ixed at the forward ends of said truck frame, sprocket wheels fixed to the truck frames adjacent their rear ends, track chains embracing the sprocket and idler wheels, means for pivotally connecting the truck frames to the main frames at a point in the rear of the sprocket wheels, and means for yieldably supporting the main frame from the forward ends of the truck frames.

4. In a tractor construction, a main frame, roller truck frames at the opposite sides thereof, idler wheels fixed at the orward ends of said truck frames, sprocket wheels fixed to the truck frames adjacent their rear ends, track chains embracing the sprocket and idler wheels, means for pivotally connecting the truck frames to the main frames at a point in the rear of the sprocket wheels, and means for yieldably supporting the main frame from the for- 'ward ends of the truck frames, driven 

